Yes, the largest seed cones are produced by cycads—short palmlike plants. They may be up to around 1 yard (1 meter) in length and weigh more that 3.3 pounds (15 kilograms). Cycads are also considered one of the most ancient forms of naked-seed plants, covering forests by about 220 to 130 million years ago. An increase in the abundance of cycads also occurred during the Jurassic period—a time that is often referred to as the “Age of Cycads.”